April 8, 2026  •  By SignMaster  •  Coroplast • Materials

The Complete Guide to Coroplast Signs: Materials, Uses, and Ordering Tips

Coroplast signs are the single most ordered product category in the wholesale sign printing industry — and for good reason. They are inexpensive, lightweight, weather resistant, and available in enough sizes and thicknesses to serve virtually every short-term signage application. If your sign shop isn't actively selling corrugated plastic to real estate agents, political campaigns, contractors, and event organizers, you are leaving consistent, high-volume revenue on the table.

This guide covers everything you need to know about coroplast as a wholesale product: what the material actually is, how to choose the right thickness, how flute direction affects your customers' installations, and how to spec orders for maximum margins without surprises. We'll also cover where SignMaster fits into your workflow as a wholesale coroplast printing partner.

What Is Coroplast? Understanding the Material

Coroplast is the brand name for corrugated polypropylene, a lightweight plastic sheet material with a twin-wall construction — two flat outer skins connected by internal flutes (the corrugated channels running through the middle of the sheet). The result is a material that is surprisingly rigid and dent resistant for its weight, especially compared to flat plastic sheets of similar thickness.

The key property that makes coroplast valuable for outdoor signage is its opaque composition. Unlike cheaper translucent corrugated plastic, true opaque coroplast prevents artwork on one side from showing through to the other — a critical feature for double-sided yard signs, where legibility from both directions matters. Always ask your supplier whether their material is opaque before ordering for double-sided applications.

Coroplast is not rated for long-term outdoor use the way aluminum or ACM is. UV exposure will gradually degrade the polypropylene over time, making it brittle. For most yard sign applications, this is irrelevant — the signs are typically used for 60-90 days and then retired. For any application requiring multi-year outdoor life, aluminum or polyethylene is the appropriate choice.

Thickness Options: 4mm, 6mm, and 10mm — Which Should You Order?

SignMaster stocks coroplast in three standard thicknesses, each suited to a different range of applications.

4mm Coroplast

The 4mm thickness is the workhorse of the political and real estate sign market. It is lightweight, inexpensive, and perfectly adequate for most standard-size yard signs where the sign is supported by an H-wire stake or wire rider. At 4mm, the sign has enough rigidity to stay flat in typical outdoor conditions and enough flexibility to survive normal handling during installation. This is the thickness most sign shops default to for high-volume, price-sensitive political sign runs and standard real estate signs up to about 18"x24".

6mm Coroplast

Step up to 6mm when you need more rigidity — particularly for larger formats (24"x36" and above), high-wind environments, or applications where the sign is being mounted to a frame or structure rather than held by a stake. The additional thickness adds meaningful stiffness while keeping the weight low enough for easy one-person installation. Many real estate offices specify 6mm for their premium listing signs to convey a higher-quality presentation.

10mm Coroplast

The 10mm thickness is the heavy-duty option, delivering maximum rigidity and impact resistance. It is commonly used for construction site signs, large-format directional signage, and any application where the sign will be handled frequently or exposed to rough conditions. The 10mm material is significantly stiffer and heavier than the thinner options, making it less suitable for applications requiring flexible stake installation. SignMaster stocks 10mm up to 4'x8'.

Flute Direction: Horizontal vs. Vertical — Why It Matters for Installation

This is one of the most overlooked spec decisions in coroplast ordering, and getting it wrong causes real problems for your customers at the job site.

The corrugated flutes inside the coroplast panel run in one direction across the full sheet. Standard coroplast ships with the flutes running horizontally (parallel to the long edge of a landscape-oriented sign). This is optimal for H-wire stake installation: the wire legs slide down the outside of the flutes and grip cleanly, keeping the sign secure and upright.

For applications where you need the wire to insert from the top of the sign (portrait orientation, or custom shapes), you want vertical flute direction — the flutes run parallel to the short edge, allowing wire insertion from above. Ordering the wrong flute direction means your customer's signs won't mount to standard H-wire stakes properly.

If you're unsure, ask your client how the signs will be installed. Standard yard sign stakes? Horizontal flutes. Post-mounted or flat-mounted? Flute direction doesn't matter as much, but horizontal is still the default. Custom installation hardware? Confirm the channel orientation required.

Design Considerations for Coroplast Signs

Bleed and Safe Zones

Like any printed product, coroplast signs should be designed with proper bleed (typically 0.125" on all sides) to prevent white edges if the print or cut is slightly off-registration. Keep important text and logos within a safe zone of at least 0.25" from the final cut edge.

Color Mode and Resolution

Submit artwork in CMYK color mode at 100-150 DPI at full size (not RGB — colors shift significantly in the conversion). For large format signs, 100 DPI at full size is standard and produces excellent results when viewed at normal reading distances.

Double-Sided Signs

For double-sided coroplast signs, supply two separate files — one for each side. Make sure both sides are designed as mirror images of each other if the sign will be read from both sides of the same road. Many designers make the mistake of sending the same file for both sides without mirroring it, resulting in a sign that reads correctly in one direction and backwards in the other.

How Pricing Works on Wholesale Coroplast

Wholesale coroplast pricing is primarily driven by square footage plus any additional die cutting or custom processing. The standard pricing model has no setup charges, no minimum quantities, and no rush fees — at SignMaster, those apply on every order regardless of size.

When quoting coroplast to your clients, a typical retail markup in the sign industry is 2x-3x wholesale cost, depending on your market and competition. The low per-unit wholesale cost on coroplast makes it a strong margin product even at competitive retail prices. On high-volume runs for political campaigns or real estate offices, the volume discounts available from a wholesale partner like SignMaster can significantly widen your margin while keeping your client's per-sign cost attractive.

Popular Coroplast Sign Applications by Industry

Ordering Coroplast Through SignMaster

SignMaster is a trade-only wholesale printer — we exist exclusively to serve sign shops, print brokers, and resellers. We never sell direct to the public, and every order ships without any SignMaster identification, so your client relationship stays yours.

94.6% of our coroplast orders ship the next business day after file approval. There are no minimum quantities, no setup charges, no color matching fees, and no rush charges — on any order, any size, any time. Shipping is free on UPS Ground shipments to the contiguous US.

To get started with wholesale coroplast printing, create a free account and submit your first order. Our sales team is available Monday through Friday, 8am-5pm CST at 1-800-757-7021 if you have questions about specifications, file prep, or pricing.

Filed under: Coroplast Signs, Materials, Ordering Guide